Wool dye of the triphenylmethane series



phonic'acids of the formular Patented Sept. 12, 1933 UNITED "sirATES PA ENT- owler 1,926,631 a Wool. DYE OF THE TRIPHENYLMETHANE SERIES Ernest Harry Rodd, Timperley, and Frederick Lawrence Sharp, Huddersfield,Ei1gland, as I signors to Imperial Chemical Industries Limited, Westminister, England No Drawing- Application August 6, 1930, Serial ---No. 473,509, and in Great Britain August 19,

(H503.CsHLCHrIILCuHDmCH:

wherein R represents an alkyl group, by oxidizing the methane hydrogen to hydroxyl, condensing the resulting carbinol with a suitable aromatic amine to form a triaminotriphenyl-methane derivative, and oxidizing the latter to the dye. As aromaticqamines only tertiary amines such as dialkylanilines, or secondary amines having a substituent in the ortho position, such as monoalkyl-o-toluidines, have hitherto been found suitable in practice; and it is well known to those skilled in the art that primary amines suchas aniline and o-toluidine are entirely unsuitable, the yield of dyestufi obtained in these cases being so meagre that to makethem on a manufacturing scale is out of the question. It is indeed generally known that such leuco compounds of the triarylmethane series as contain primary amino groups cannot be satisfactorily oxidized to the corresponding triarylmethane dyestuff.

The present invention is based on the discovery that m-2-xylidine (2-amino-1:3-dimethylbenzene) condenser with diaralkyldialkyldiaminobenzhydrol disulphonic acids to give leuco compounds which are smoothly and satisfactorily oxidized to triphenylmethane' dyestuffs. This behavior of m-2-xy1idine, contrary to that of its congeners, could not be foreseen.

The process of manufacture in accordance with our invention consists preferably in an oxidative condensation, wherein we take asstarting out materials m-2-xylidine on, the one hand and diaralkyldialkyldiaminomethane disulphonic acf 'idson the other, and conduct the axidation to the so-called hydrol, condensation of the leuco 4; Claims. (01. 260-457) obvious thatthe reaction maybe carriedout in other ways.

The reaction may be represented in, general terms by the following equations;

a i i I i- HS03-C H4-CH1-NC H4-(f C H4-NCH2C6H4S03H on is condensed with 2-amino-1.3-dimethyl benzene to form a leuco compound having the formula R Y H R HsC CHa NHa In the above formula R represents an alkyl group and'any aralkyl group may be used instead of the benzyl group.

Our invention is illustrated, but not limited by the following example, in which the parts are by weight. 7

Example 7 xylidine. The solution is stirred atthis temperature for 12 hours, during which time the violet color develops, and the reaction is completed by heating for a short period at 80 C. The precipitated chromium residue is filtered off and the dyestuff separated by the addition of common salt of the filtrate. The dyestuif forms a tarry mass which, after drying, can be ground to powder. It is readily soluble in water to a reddishviolet solution.

The dye in the form of the free acid has the following formula:

' soul 7 V CzH N Cz r-N i (JaHr-SOa v A ceptional interest. Thedyeings are of very good fastness to washing and milling. The dyestuffs I are also suitable for dyeing'union'inaterials.

ments of this invention may be made without departing from the spirit thereoflit is to be understood that we do not limit ourselves to the foregoing examplesor descriptions except as indicated in the following patent claims. -Wec 1aim: U 2

1. A dyestufi having. the following general formula: g

I f1 1 HSOa-C5H4-CHz-Ni-CeH4C -CgHr-N-CHyCaHg-SOaH wherein R represents an alkyl group and the benzyl group may be replaced by any aralkyl group. I

12. A dyestuff having the following general formula:

SOgH.

3. The processof preparing a dyestuff of the AS many apparently widely. different embody triphenyl methane S6118S which comprises condensing a diaralkyl-dialkyLdiamino-diphenylbenzhydrol disulphonic acid with 2- amino-123- dimethyl benzene and. oxidizing the resulting leuco compounds.- w

4;. The processof preparing a dyestufi of the triphenyl methane series which comprises con densing dibenzyl-rdiethyl-diamino diphenylmethane disulphonic'; acid with Z-airfino-dfi-dimethyl benzene and oxidizing the resulting leuco cornpound.-. I

ERNEST HARRY Bonn.

FREDERICK. LAWRENCE- srrARB. I v 

